The present invention relates to a plant for handling, such as by transporting, crushing, screening or processing particulate materials such as sand, gravel, crushed aggregate, soil, peat or recoverable excavated material. Preferably the invention is used with a screening plant or a part thereof. The screening plant should be of the type which includes at least one feed station, onto or into which material to be transported, crushed, screened, handled or processed in other ways is brought or fed for discharge onto a conveyor which feeds the material to a location for storing or to a device for further transport or for crushing, screening, handling or processing.
Materials to be used in the superstructure, such as the subbase, base or bearing course and surfacing for streets and roads, air fields or railroads, must meet or comply with certain requirements. Streets and roads with a sub-base however, can, after a certain time, show extensive tracking in the roadway. Tracking, which might cause aquaplaning on surfaced streets and roads, depends to a large degree on whether the material in the subbase has settled. The reason for the settling often seems to be the too small variations in size of the particles or grains in the material for the subbase. A larger particle size distribution, i.e. larger variations in the particle or grain size, and optimal carrying capacity of the included stone material is therefore aimed at. However, this has substantially limited the material which can be used for subbases for streets and roads. Large areas of the country are short of acceptable material. The building of new roads therefore requires longer transports of material complying with the requirements, especially within the areas short of acceptable material, whereby the costs for the road building are substantially increased.
To be able to increase the exploitation of existing resources, one has started to mix various materials, where one or more of the materials normally could not be used as superstructure materials, but the mixture has the required properties. This means a saving of material and permits use of otherwise unusable material. In certain cases, only otherwise unusable material is being used. Alternative materials such as crushed rock, rock flour, lime, cement, gypsum, hardcore, ore, and ashes can be used, resulting in an additional saving of the resources and an environmental protective factor.
Existing mixers or mixing plants for the abovementioned mixing of superstructure materials are large and complex separate units which are expensive and can not be found wherever mixing is required or suitable to carry out.